I have a Long discontinued Lepold VariX-II 2-7x33mm shotgun scopes mounted on two of my 870s for use as dedicated turkey guns. Had to make the transition from fiber optic irons to scopes due to my eye sight changing.
Been using scopes for 4 seasons and are very happy. YES there is a slight trade off in being more difficult in picking up fast moving or running birds who you have spooked after they were in range, but EVERY other long gun I own is scoped so putting one on my turkey gun was a natural transition.
Last year I came upon a deal on Sig Romeo-5's for $90 W/shipping so I bought two one for each of my sons turkey guns and they love them and are perfectly suited for use on turkey guns and are in my opinion superior to iron sights.
Only way you will know is give a scope a try, but be sure to do a enough practice shooting with one while seated to be totally comfortable using one.